GE's First All-New Turbine in 20 Years is Optimized for Renewables

Working Better With Solar and Wind

Ideally, the electricity that you're using would come from clean and renewable sources, and the intermittency of many of those (solar, wind, wave...) wouldn't be a problem thanks to various ways to store power, such as large reservoirs connected to hydro, pumped storage, and grid-scale liquid metal batteries, and thanks to a smarter and more inter-connected grid.

But while we transition to that glorious green future, we still need to use natural gas power plants that are quick to fire up to pick up the slack when the wind stops blowing or the sun stops shining. But the gas turbines used in most of these plants are based on designs that are a couple of decades old, and they were not built with renewable in mind. That's why it's a big deal that GE has an all-new turbine design that was created with this problem in mind.

The FlexEfficiency turbines will be able to rapidly increase or decrease power output. This is important when gas generation facilities are combined with renewables like wind and solar. Gas turbines designed in the 80s, explained Gebhardt, were optimized for efficiency, overall availability, and reliability; not for how fast they start up or shut down. And fast startups and shutdowns are tricky, he explained, because of the changes and stresses different parts of the turbine go through in response to the dramatic changes in temperature. The new turbines are incorporating better materials for thermal management, he said, including nickel-based superalloys and single-crystal materials along the hot gas path. They also use better cooling systems, integrate a better understanding of the clearances involved when different parts expand and contract at different rates, and rely on physics-based models for combustion control.

Basically, the new turbines are designed for 21st century realities. Hopefully they won't be needed at some point - I hope GE is investing in grid-scale liquid metal batteries! - but for now they serve an important purpose.

As a result of the new design, Gebhardt said, a 750 megawatt system can reduce its power output to about 100 megawatts in about 6 and a half minutes and come back up again just as fast; previous facilities could only dial back to about 200 megawatts without fully shutting down and took several minutes longer to come back up.

This higher flexibility will no doubt allow more intermittent renewables to be incorporated into the grid. I know it's not a problem most of us think about, but grid operators have to be sure that if there's a day without wind and sun, that the power keeps flowing to hospitals and refrigerated warehouses and such...